Method of tempering spiral springs



(No Model.)

F. SEDGWIOK. METHOD OF TEMPERING SPIRAL SPRINGS.

No. 401,721. Patented'Apr. 16, 1889.

l/x'frzeasea. In Me 71/607":

UNITED STATES PATENT OFFICE.

FREDERICK SEDGIYICK, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE AMERI- (AN SPRING COMPANY, OF ILLINOIS.

METHOD OF TEMPERING SPIRAL SPRINGS.

SPECIFICATION forming part of Letters Patent N0. 401,721, dated April 16, 1889.

Application filed December 2, 1887. Serial No. 256,741. (No model.)

1'0 a/ZZ whom nmy concern: preference, wholly or partially filled with mer- Be it known that I, FREDERICK SEDGWICK, cury, as shown in Fig. 1, for the purposes hereof Chicago, in the county of Cook and State inafter stated. of Illinois,have invented a certain new, useful, C is a mandrel or former mounted in bear- 5 and Improved Method of Tempering Spiral ings c c, Fig. 2, so as to be readily removed Springs, of which the following is a descriptherefrom. tion, reference being had to the accompany- D is a shaft loosely mounted in abeariug, (1, ing drawings, tormin g a part of this specificasecured to the trough B. Upon the inner end tion, in which like letters of reference in the of said shaft is a gear-wheel, I), which en- IO ditt'erent figures designate like parts. gages with a gear, t", rigidly attached to the .l Ieretolore in the tempering of spiral mandrel O. springs it has been customary to wind the D is a crank by which the shaft .is rotated, tempered wire when cold upon a former of the and D is a worm-gear, which engages with a desired shape. This method has been found rack, E, attached, by means of standards E, to [5 to be objectionable, in that the molecules of the base A.

the metal upon the outside of the coil have F is a reel, and G is a wire extending therebeen strained or stretched, while those upon from to the mandrel (I, to which one end is the insidehave been undulycompressed, thus attached, as shown in Fig. 9. greatly weakening and impairing the value II is a standard attached rigidly to the base 20 ot' the spring. To meet this difficulty and to A, an d to which in turn is secured, and prefrestore the nature to the spring, it has erably insulated therefrorma spring-clamp,J, been customary, after forming the same, as and binding-post J. above stated,to submit it in an. oven or mutiie K is a dynamo, one pole of which is conto a heat of about 600 Fahrenheit, or there nected with the binding-post J by means of 25 about, for a sutticient time to cause the molea wire, 7.2, and the other, by a wire, 71 to a culesot' the metal to assume their normal binding-post, B, secured to the trough I and relations. While this strengthens, and in a having a metal strip, I5 which extends into measure imparts new life to the spring, yet it the mercury of said trough.

does not accomplish the desired result. More- The wire G passes from the reel through 0 over, the reheating of the metal is injurious the clamp .I, and thus that portion between in itself and should be avoided,if possible. said clamp and the mandrel serves to com- The object of my invention is to provide a plete the electric circuit with the wires 7t 70', method. whereby a steel wire or ribbon may said mandrel thus forming one pole of the be formed into a spiral or coil while the steel circuit with the wire to be tempered. As is heated to a rod heat and is soft or ductile, soon as the end of: the wire is attached to the and while in this condition and form chilled mandrel and the electric circuit closed the or tempered, the whole being done simultawire between the mandrel and clamp J bencously and in one operation, and serving to comes heated, when the crank l) is turned, produce a hot-set spring, thus obviating the thus winding the heated wire upon the man- 0 4o defects above described, all of which is heredrel. The mandrel being cold, by virtue of its inatter described, claimed, and shown in the continual contact with the mercury, serves to drawings, in which suddenly chill the wire and impartthereto a Figure l is a side view of a reel, mandrel, spring-temper, provided the strength of the cooling-bath, and dynamo-electric machine, electric currentis so regulated as to cause the 5 the whole constituting my improved apparaproper degree of heat, which is indicated by tus for coiling and tei'npering springs, and a dull or low-red color. The cooling-bath into Fig. 9 is a plan view thereof. which the wire is wound also aids to chill said Referring to the drawings, A represents a wire. As the mandrel is revolved, it is also base or support, upon which is loosely placed moved longitudinally by means of the worm I00 50 an oblong vessel, 13, adapted to slide across I) and rack E, so as to impart the desired said base in guides h h. Said vessel is, by pitch to the spiral. IIpon reaching the end of the mandrel the electric circuit is broken and the spring removed, when the operation may be repeated.

\Vhile I prefer to revolve the mandrel in a bath of mercury, it is obvious that any other cooling medium may be employed which will not tend to impair the electric contact of the wire with the mandrel. To this end the mandrel may be made hollow, and water may be made to circulate therein. In the latter event the strip B which might form a brush, should be brought into direct contact with the mandrel, so that the latter may form one pole of the electric circuit.

I am aware that it is old in the manufacture of coiled springs to successively and continuously heat, harden, and temper, and then coil the wire into spring form while it yet retains its tempering-heat, and I make 'no claim to such method; but form the coil While the I metal is in such a ductile condition as to require chilling to give it a' temper, as distinguished from coiling after a temper has been imparted to it. To accomplish this result, it is obvious that the wire should be heated to a red heat as nearly as possible to its point of contact with the mandrel. This is best effected by employing electric heat and causing the mandrel to form one electrode. In coiling small wire, which only retains its heat for an instant, the importance of this feature is manifest. The result of this method is a hotset spring bent or formed While the metal is soft or ductile.

One advantage of said method, aside from its cheapness, is, that the wire, being bent upon the mandrel while hot and chilled thereon, will retain its strength and rr siliency to the utmost, and will require no furthertreat ment than the mere drawing of the temper in any well-known way, to make a perfect spring.

Having thus described my invention, I claim The method, substantially as herein shown and described, in the manufacture of coiled springs, which consists in simultaneously heating the steel wire or strip to redness or a ductile condition, winding and chilling the same upon a former or mandrel, and afterward drawing the temper in any well-known way.

FREDERICK SEDGWICK. Witnesses:

D. H. FLETCHER, J. B. HALPENNY. 

